Bag stacking assembly for a bag making machine



BAG STACKING ASSEMBLY FOR A BAG MAKING MACHINE Filed May 25, 1956 Aug. 4, 1959 F. P. WlNESETT 6 Shets-Sheet 1 OWN EN mmN wmN

INVENTOR FRANK P. WINESETT NP BY, W gz/ A'ILI'ORNEY Aug. 4, 1959 F. P. WINESETT BAG STACKING ASSEMBLY FOR A BAG MAKING MACHINE Filed May 25, 1956 2 RT n a vmN m m 6 m m mm e e K h N s A 6 m ATTORNEY BAG STACKING ASSEMBLY FOR A BAG MAKING MACHINE Filed May 25. 1956 Aug. 4, 1959 F. P. WINESETT 6 Sheets-Sheet I5 INVENTOR FRANK P. WINESETT lllllll'll i No oN .3 v0

AITORNEY BAG STACKING ASSEMBLY FOR A BAG MAKING MACHINE Filed May 25, 1956 Aug. 4, 1959 F. P. WINESETT 6 Sheets-Sheet 5 I INVENTOR v FRAflK P. WINESETT BY 4,40% :5 /Q /11M a ATTORNEY United States Patent BAG STACKING ASSEMBLY FOR A BAG MAKING MACHINE This invention pertains to a bag stacker for use with a bag making machine and more specifically relates to a bag stacker adapted for use with a machine for making bags of polyethylene film or the like.

It is very diificult to handle and stack bags made of polyethylene film since such material, being an excellent insulator, readily builds up static electricity from frictional contact, and by contact with and separation from other surfaces. The static charge on the polyethylene film tends to cause the bags to stick to any surface with which they come in contact.

An object of the invention is to provide an improved bag stacking mechanism.

Another object is to provide an improved mechanism 7 for receiving bags successively from a bag making machine or other suitable source, and for conveying the bags away therefrom to a place of discharge.

Another object of the invention is to provide an improved mechanism for stacking the bags in piles readily distinguishable from each other and each containing a predetermined number of bags.

Another object of this invention is to provide an efiicient mechanism for stacking bags of polyethylene or similar material wherein any static charge on the surface of the bags is discharged therefrom as the bags leave the bag making machine, and wherein the bags are subsequently handled in such a way as to remain out of frictional contact with any surfaces until they are actually deposited on the stack of bags being formed in order to prevent any new static charges from forming thereon.

Various other objects will be apparent from the following description and accompanying drawings in which:

Fig. l is a plan view of the stacker of the present invention with the upper flanges of the channel-shaped side frame members removed to show various details therebeneath.

Figs. 2A and 23 when taken together in end-to-end relation with each other form an enlarged vertical section taken on line 2-2 of Fig. 1.

Fig. 3 is a transverse vertical section taken on line 33 of Fig. l.

Fig. 4 is a fragmentary side elevation of the machine taken along line 44 of Fig. 1.

- Fig. 5 is a fragmentary side elevation of the machine taken along line 5-5 of Fig. 1.

Fig. 6 is a fragmentary perspective View illustrating a portion of the mechanism for controlling the cycling action of the delivery conveyor.

Fig. 7 is a wiring diagram of the switches controlling the cycling mechanism shown in Fig. 6.

Fig. 8 is a fragmentary perspective of one of the gripping assemblies on the stacking conveyor.

Fig. 9 is a perspective view of the mechanism for eliminating air from between the bags as they are stacked one upon another. 8

Figs. 10, 11 and 12 are schematic views illustrating the action of the bag stacking mechanism during successive phases of its operation.

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The bags to be stacked by the machine of the present invention are produced by a bag making machine from a flattened tube of material having a series of transversely extending heated sealed zones spaced longitudinally of the tube. Each of the heat sealed zones represents the closed bottom edge of a bag. As the tube of material issues from the bag making machine, it passes between the knife mechanism A thereof and is severed thereby immediately adjacent and behind each of the heat sealed zones into the individual bags 1.

Each bag J flowing from the knife assembly A rests on and moves along the upper surfaces of a plurality of short endless belts B, and flows over the rear pulleys C about which said belts are trained (the forward pulleys about which said belts are trained being located immediately adjacent the rear of the knife assembly A). As the rearmost or sealed edge of the bag I leaves the knife assembly A, the bag is held against the upper surfaces of the belts B by a transverse bar D (Figs. 2A and 10) of the bag stacking conveyor generally indicated E. The rearmost edge of the bag I is gripped by a gripper unit F on the stacking conveyor and the bag is suspended therefrom as it is moved to the left as viewed in Figs. 2A and 2B until released by the unit F.

and permitted to drape itself transversely across a delivery conveyor G. At the same time that the bag is released by the unit F, the arms of an air eliminating mechanism H are rotated downwardly to depress the bag I against the upper surface of the bag previously deposited on the conveyor G and thus eliminate air from between the contacting surfaces of the two bags.

Referring now to Figs 2A, 4 and 5 the knife assembly A comprises a pair of socket members 13 and 14 adapted to be received on the rear ends of two rods 15 and 16 extending rearwardly from the bag making machine. Two side plates 17 and 18 are fixed to and extend upwardly from the socket members 13 and 14, respectively, and are connected at their upper ends by a top plate 19. A pair of draw rollers 20 and 22 are mounted between the side plates 17 and 18 one above the other with their longitudinal axes extending transversely of the machine. A drive chain 24 (Fig. 4) is driven intermittently in timed relation with the bag making machine (not shown) and drives a sprocket 26 fixed to the lower roller 22. The upper roller 20 is mounted for limited vertical movement relative to the lower roller'22 by a pair of bearings 28 and 30 which are slidably mounted in vertical groves 32 and 34 in side plates 17 and 18, respectively, of the knife assembly A. A pair of springs 40 and 42 normally urge the upper roller 20 downwardly into frictional contact with the lower roller 22 whereby as the lower roller is rotated by means of the drive chain 24, the upper roller will rotate therewith.

Each of the rollers 20 and 22 is provided with a plurality of circumferential grooves in the manner indicated at 44 and 46, respectively (Fig. 2A). A pair of upper and lower transversely extending guide rods or bars 48 and 50 are fixed to opposite side plates 52 and 54, the 1 upper bar 48 being above and the lower bar 50 being below the plane of the bight between the rollers 20 and 22. A plurality of guide fingers 56 are fixed to the under surface of the upper guide bar 48 and'extend rearwardly therefrom and are received in the grooves 44 in the upper roller 20. Similarly, a plurality of fingers 58 are fixed to the upper surface of the lower guide rod 50 and extend rearwardly therefrom and are received within the grooves 46 on the lower roller 22. Immediately rearwardly of the rollers 20 and 22 an upper stationary knife holding bracket 60 is fixed to the top plate 19 of the knife assembly A and extends downwardly therefrom.

A horizontally extending knife blade 62 is fixed to the lower end of the knife holder 60. A lower knife holding member 64 is mounted for vertical movement relative to the upper knife holding member 60 and carries at its upper end a substantially horizontally extending knife having a cutting edge 66. The knife edge 66 is inclined to the horizontal, and when the lower knife holding member 64 is moved upwardly relative to the upper knife holding member 60 the two knife blades 62 and 66 cooperate to sever the tube of material transversely thereof.

As best seen in Figs. 4 and 5, the lower knifeholding member 64 is provided with two outwardly extending pins 68 (Fig. 4) and 70 (Fig. one adjacent each end thereof. The pin 68 extends outwardly through a vertical slot 72 formed in a guide plate 74 fastened to the left side plate 18. A tension spring 76 is connected to a pin 78 fixed to the top plate 19 of the knife assembly A and the lower end of the spring 76 is hooked around the pin 68. In a similar manner the pin 70 at the right end of the lower knife holding member 64 extends through a slot 80 in a guide plate 82 fixed to the right side plate 17 of the knife assembly A. A tension spring 84 is hooked to a pin 86 fixed to the top plate 19 of the knife assembly A and the lower end of the spring 84 is hooked around the pin 70.

A pair of forked crank arms 88 and 90 are fixed to the opposite ends of a transversely extending shaft 92 mounted for rotation in the side plates 17 and 18 parallel to and rearwardly from the lower knife holding member 64. The arms 88 and 90 extend forwardly from the shaft 92 and the forked ends 94 and 96, respectively, of the arms 88 and 90 embrace the pins 68 and 70 on the knife holding member 64, whereby clockwise rotation of the shaft 92 as viewed in Figs. 2A and 4 will cause the lower knife holding member 64 to be moved downwardly against the tension of the springs 76 and 84. A crank arm 98 is fixedly secured to the central portion of the shaft 92 in the manner indicated in Fig. 2A. A clevis pin 100 connects the lower end of the arm 98 with a push rod 102 operated by a cam on a cam shaft of the bag making machine (not shown).

Located immediately rearwardly of the knife blades 62 and 66 is a mechanism for holding the tube of material stationary as it is being severed by the knife blades 62 and 66. This mechanism comprises an upper abutment member in the form of a transversely extending bar 104. One end of the bar 104 (Figs. 2A and 5) is provided with a suitable vertically extending bore (not shown) through which a rod 106 extends. A suitable washer 108 and cotter key 110 are mounted on the rod 106 below the bar 104 to retain the bar thereof. The rod 106 is formed integral with and extends downwardly from a threaded stud 112 which extends upwardly through a suitable aperture in the top plate 19 of the knife assembly A, and is adjustably secured with relation htereto by a pair of nuts 116 threadedly received on the stud 112, one above and one beneath the plate 19. .A compression spring 118 is confined between the upper surface of the bar 104 and the lower end of the stud 112 and normally urges one end of the bar 104 to its lowermost position relative to the rod 106.

The other end of the bar 104 (Fig. 4) is similarly provided with a vertical bore which slidably receives a rod 120. The bar 104 is retained on the rod 120 by a suitable washer 122 and cotter key 124. The rod 120 is formed integral with the lower end of a stud 126 adjustably secured to the top plate 19 in the same manner as is the stud 112. A compression spring 128 normally urges said other end of the bar 104 to its lowermost position relative to the rod 120.

As best seen in Fig. 2A a lower bar 130 extends transversely of the knife assembly A in opposition to and below the bar 104. The bar 130 is guided in any suitable manner adjacent its end portions for vertical reciprocatory movement toward and away from the upper bar 104. A link 132 is connected to one end of the bar 130 and extends downwardly therefrom. The lower end of the link 132 is connected by a pivot pin 134 to the forward end of an arm 136 pivotally secured at its rearmost end to the outer surface of the tubular socket member 13 in the manner indicated at 138 in Fig. 2A. A cam follower roller 140 is mounted for rotation on a pin 142 connected to the arm 136 intermediate its ends. The roller 140 rides on the surface of a cam 144 fixed to a transverse shaft 146 journalled for rotation at one of its ends in a depending side plate fixed to the socket member 13 (Fig. 5), and at its other end in a bracket 147 fixed to a plate 149 connected between the lower end of the plate 145 and a spacer block 151 fixed to the tubular member 14 (Fig. 4). A similar link and arm (not shown) are connected to the other end of the bar 130 and cooperate with a similar cam (not shown) adjacent the other end of the shaft 146 whereby rotation of the shaft 146 will cause the bar 130 to be periodically moved upwardly against the lower surface of the bar 104 to clamp the tube of material therebetween as it is being severed by the knife blades 62 and 66. The shaft 146 (Fig. 5) is provided adjacent one end with a sprocket 148. A drive chain 150, continuously driven by the bag making machine (not shown), engages the sprocket 148 and provides continuous rotation of the shaft 146 in timed relation with the action of the draw rollers 20 and 22 and the knife blades 62 and 66.

The bag stacking mechanism E comprises a pair of side plates 152 and 154 fixed to the tubular members 13 and 14, respectively, and extending rearwardly therefrom. A pair of channel-shaped side frame members 156 and 158 (Fig. 3) are fixed to the upper edges of the side plates 152 and 154 and extend rearwardly therefrom in parallel spaced relation with each other, and a transverse rear plate 157 connects the rear ends of the side members 156 and 158. A front plate 159 connects the front ends of the side members 156 and 158. A shaft 160 extends transversely between and is suitably journalled for rotation in the side plates 152 and 154. The pulleys C previously mentioned are fixed to the shaft 160 at points spaced equidistant therealong. An idler shaft 162 is journalled for rotation between the side plates 152 and 154 forwardly of and slightly above the shaft 160 immediately adjacent the rear surface of the knife blades 62 and 66. A plurality of smaller pulleys 1-64v are fixed to the shaft 162 in opposition to the pulleys C on the shaft 160. The belts B previously mentioned are trained one about each of the pairs of pulleys C and 164 in the manner best illustrated in Figs. 1, 2A and 3.

A shaft 166 extends between and is suitably journalled for rotation in the side members 156 and 158 adjacent the forward end thereof and a sprocket 168 is fixed to the right end of the shaft 166 (Fig. 3). The previously mentioned continuously driven drive chain 150 (Fig. 5) which drives the sprocket 148 on the shaft 146 also drives a sprocket 171 fixed to a stub shaft 172 rotatably journalled on the side plate 152. A spur gear 173 fixed to the stub shaft 172 meshes with and drives a gear 174 fixed to one end of a shaft 175 extending transversely between and rotatably journalled in the side plates 152 and 154. A sprocket 176 (Fig. 4) is fixed to the other end of the shaft 175, and a drive chain 178 meshes with and interconects the sprocket 176 and a sprocket 180 on the shaft 160 and the sprocket 168 on one end of the shaft 166. The chain 178 passes over an idler sprocket 184 rotatably mounted on a stub shaft 186 fixed to the side member 158 and thence returns to the sprocket 17 6.

A shaft 188 (Fig. 1) is adjustably secured between the side members 156 and 158 adjacent the rearmost ends thereof. A pair of adjusting studs 190 and 192 are fixed to the shaft 188 adjacent the ends thereof and extend rearwardly therefrom to suitable apertures provided in the rear plate 157. A pair of nuts 194 and 196 are threaded on the studs 1'90 and 192, respectively, adjacent the outer surface of the plate 157 and serve to adjust the position of the shaft 188 longitudinally of the side plates 156 and 158. A pair of sprockets 198 and 200 are fixed to the shaft 166, one adjacent the inner surface of each of the side members 156 and 158. A similar pair of sprockets 202 and 204 are rotatably mounted on the shaft 188, one adjacent the inner surface of each of the members 156 and 158. An endless conveyor chain 206 is trained around the sprockets 198 and 202 and a similar endless conveyor chain 208 is trained around the sprockets 200 and 204.

The gripping assemblies, each generally indicated at F,

are fixed to the chains 206 and 208 at points spaced equidistant from each other along said chains. As best seen in Figs. 2A, 2B and 8, each of the gripping assemblies F is preceded by one of the bars D previously described. One end of the bar D is secured by a machine screw 212 to a tab 214 extending laterally inwardly from a special link 216 on the chain 208. The opposite end of the bar D is connected in a similar manner to the chain Each gripper assembly F comprises a second bar 218 connected by a machine screw 220 to a tab 222 on a special link 224 on the chain 208 rearwardly of the link 216 with respect to the direction of movement of the chain. The other end of the bar 218 is similarly connected to the chain 206. A bearing block 226 is fixed to the rear surface of the bar 218, when considered with respect to the direction of motion of the chain 208, adjacent the end of the bar 218 shown in Fig. 8. A similar block 228 (Fig. l) is fixed to the rear surface of the bar 218 adjacent the opposite end thereof. A bar 230 extends between the blocks 226 and 228 and is provided at its opposite ends with cylindrical projecting pins 232 and 234 which are rotatably received Within suitable apertures in the bearing blocks 226 and 228, respectively. A crank arm 236 is connected to the end of the pin 232 by a set screw 237. The outer end of the crank arm 236 is pivotally connected by a pivot pin 238 to a link 240. The opposite end of the link 240 is provided with a longitudinally extending slot 242 through which a pin 244 projects. The pin 244 is connected to the chain 208 rearwardly of the special link 224 when considered with respect to the direction of motion of the chain 208. A torsion spring 233 surrounds the pin 232 and'is connected between the bearing block 226 and a collar 235 fixed to the pin 232. A similar torsion spring 237 is connected between the bearing block 228 and a collar 239 fixed to the pin 234.

A plurality of spacer blocks 246 are fixed to the upper surface of the bar 230 at points spaced equidistant from each other along the entire length of the bar. A spring finger 248 is fixed adjacent the top of each of the spacer blocks 246 and. extends therefrom toward the bar 218 and engages the upper surface thereof in order to grip a bag I therebetween in the manner hereinbelow described. A retaining plate 250 is mounted above each of the spring fingers 248 and a pair of machine screws 252 project through suitable apertures in each retaining plate 250 and the associated spring finger 248, and are threadedly received in the associated. block 246.

From the foregoing description, it may be seen that as the chains 206 and 208 progress around the sprockets 198 and 200 the bar 218 will initially move away from the spring fingers 248 since the bar 230 will still remain in its horizontal position due to the linkage of the crank arm 236 and the link 240. When the chains again straighten out upon leaving thesprockets 198 and 200 the spring fingers 248 will be rotated into contact with the upper surface of the bar 218. It will be noted that the spacing of the spring fingers 248 is such that each of the fingers is located laterally between the belts B previously described whereby the spring fingers are adapted to grip the rear edge of a bag I resting on the upper surface of the belts B, when considered with respect to the direction of movement of the bag, as the gripping assembly F rotates about sprockets 1'98 and 200. The bag will be held by and suspended from the gripping assembly F until the gripping assembly progresses around the sprockets 202 and 204 and the spring fingers 248 are again moved away from the bar 218 to release the bag and deposit it on the upper surface of the transversely extending discharge conveyor G previously described.

The mechanism H for eliminating air from beneath the bag thus discharged is best illustrated in Figs. 2A, 2B and 9 and comprises a pair of depressing members 260 and 262 fixedly secured to two transversely extending shafts 264 and 266, respectively, each rotatably mounted between the side members 156 and 158. The shaft 266 is provided adjacent its right end with a forwardly extending arm 268 having a cam follower 270 fixed to its outer end. An actuating cam 272 is fixed to a sprocket 27 4 rotatably mounted on a stub shaft 276 fixed to and extending inwardly from the side member 156. A drive chain 278 engages the sprocket 274 and a sprocket 280 (Figs. 1 and 10-12) fixed to the shaft 166. The left end of the shaft 266 is provided with a sprocket 282 and a similar sprocket 284 is fixed to the left end of the shaft 264 in Fig. 9. A connecting chain 286 has one of its ends fixed to the upper portion of the sprocket 282 and extends around the forward portion of and beneath the sprocket 282 and rearWa-rdly therefrom beneath the sprocket 284 and around the rearmost portion thereof with the opposite end of the chain fixed to the upper portion of the sprocket 284. A torsion spring 288 surrounds the right end of the shaft 264 (Fig. 9). One end of the spring is fixed to the side plate 156 and the other end is fixed to a collar 290 rigidly secured to the shaft 264. Rotation of the shaft 266 in a counterclockwise direction as viewed in Fig. 9 under the influence of the cam 272 will cause similar counterclockwise rotation of the shaft 264 thus swinging the presser members 260 and 262 downwardly forcing the bag down against the upper surface of the discharge conveyor G (Fig. 12). Upon release of the cam 272 the torsion spring 288 will rotate the shafts 264 and 266 back to their original position (Fig. 10) wherein the presser members 260 and 262 extend in a horizontal plane above the level of the lower runs of the chains 206 and 208 and consequently above the path of bags carried by the gripping assemblies F.

The discharge conveyor G comprises a pair of side channels 292 and 294 supported at one of their ends from a shaft 296 and at their opposite ends by a pair of legs 298 and 300, respectively. A conveyor belt 295 is trained around two end rollers not shown and rests on intermediate rollers such as shown at 297 in Fig. 2B. The end roller at the right end of the conveyor G is splined to the shaft 296 whereby the conveyor G may be shifted longitudinally of the stacking conveyor E to accommodate bags of various lengths, while remaining in driving engagement with the shaft 296. The shaft 296 is journalled for rotation at its rear end in a suitable bearing block 299 mounted on one of the rear legs of the conveyor mechanism E and at its forward end in a bearing 302 fixed to the side plate 152 previously described.

As best seen in Figs. 2A and 3, the forward end of the shaft 296 is provided with a bevel gear 304 meshing with a companion bevel gear 306 fixed adjacent one end of a shaft 308 suitably journalled between the side plates 152 and 154. The other end of the shaft 308 is provided with a gear 310 fixedly secured thereto which meshes with a companion gear 312 rotatably mounted on the shaft previously described. A magnetic clutch 314 is mounted on the shaft175 and when energized couples the gear 312 to the shaft 175 for rotation therewith. The magnetic clutch 314 is periodically energized to drive the shaft 308 and thus the shaft 296 of the conveyor G, to separate the bags being deposited thereon into groups each containing a predetermined number of bags.

The mechanism for cycling the action of the discharge conveyor G comprises a worm wheel 316 (Fig. 3) fixed to the shaft 146, previously described, which meshes with a worm gear 318 fixed to a shaft 320 journalled for rotation in a bearing 322 (Figs. 4 and 5) fixed to the under surface of the knife assembly A adjacent one end thereof. A plate cam 324 is fixed to the shaft 320 for rotation therewith and is provided with a plurality of V-shaped notches 326 at points spaced equidistant about its periphery. A first microswitch 328 (Figs. 4 and 6) is fixed to the bearing housing 322 and the actuating arm 330 of the microswitch 328 engages and rides on the peripheral surface of the plate cam 324. A second microswitch 332 is fixed to the bearing housing 322 and the actuating arm 334 therefor engages and rides on the peripheral surface of an actuating cam 336 fixed to the left end of the shaft 146 (Fig. 6). The cam 336 comprises a pair of identical cam plates 338 and 340 (Fig. 4) which may be fixed to the shaft 146 in positions rotated with respect to each other to control the length of the period of actuation of the switch 332. The cam plates 338 and 340 are held in their adjusted position by a plate 342 adjacent the outer surface of the outermost plate 338 and a pair of machine screws 344 extending through the plate 342 threadedly received in a collar 346 fixed to the shaft 146.

Referring now to the wiring diagram of Fig. 7, it will be seen that the current coming from a transformer 350 passes through a bridge rectifier 352. From the rectifier 352, current passes through a line 354, one of the switches 328 and a line 356 to the magnetic clutch 314. From the clutch 314, the current passes through a line 358, the other switch 332 and a line 360, back to the rectifier 352. Thus the magnetic clutch 314 will remain de-energized unless both the switches 328 and 332 are closed at the same time. Switch 332 is a normally open switch and is closed by the cam 336 upon each rotation of the shaft 146. The magnetic clutch 314 however remains de-energized until one of the notches 326 in the cam plate 324 approaches the arm 330 of the switch 328 and permits the switch 328 to be closed by the action of the arm 330 dropping into the notch 326. In this manner, the frequency of the notches 326 on the cam plate 324 controls the number of bags in each group on the conveyor G and the relative spacing of the cam plates 338 and 340 controls the amount of movement of the conveyor G and hence the spacing between adjacent groups thereon.

In order to eliminate the build up of static electricity on the film two static eliminators are incorporated in the machine. One of the static eliminators 362 is located immediately in front of the guide bar 50 and extends parallel thereto between the plates 52 and 54 (Figs. 1, 4 and The other static eliminator 364 extends between the side plates 152 and 154 adjacent the rollers C (Figs. 2A, 3, 4 and 5). The two static eliminators are alike and only the static eliminator 364 will be described in detail. The static eliminator 364 comprises a rod having a plurality of radially extending recesses 366 formed therein as best seen in Fig. 3. Each of the recesses contains an outwardly facing point 368. The static eliminators are connected to a high voltage source of alternating current and the discharge from the points toward the film ionizes the air in the vicinity of the film and permits any static charge existing thereon to discharge therefrom.

In the operation of the device the bags intermittently discharged through the knife assembly A and severed thereby from the tube of material issuing from the bag making machine. Referring now to Fig. 10, the bag I is conveyed on the upper surfaces of the belts B and fiows downwardly over the rear surface of the pulleys C. At about the same time that the bag is severed by the knife blades 62 and 66 (Fig. 2A), the bar D contacts the upper surface of the bag I and the bag is clamped between the bar D and the belts B. As the chain 208 progresses around the sprocket 200 the bag I, the bar D and the belts B all move rearwardly at the same speed and the bar 218 moves downwardly into contact with the upper surface of the bag I adjacent the edge thereof. Further movement of the chain 208 about the sprocket 200 brings the pin 244 into substantially horizontal alignment with the supporting link 224 (Fig. 8) of the bar 218 and the'bar 230 is rotated clockwise, as viewed in Fig. 10, relative to the bar 218 to bring the spring fingers 248 into engagement with the bottom surface of the bag I and thus clamp the bag between the fingers 248 and the bar 218. Due to the elongation of the slot 242 within which the pin 244 is engaged, the pin 244 does not prevent the spring 233 from turning the bar 230' far enough to press the fingers 248 into tight, abutting engagement with the bar 218 when the links 224 carrying the bar 218 and the link that carries the pin 244 are all within the lower runs of the chains 206 and 208. Thus, the linkage that effects turning the fingers 248 toward and away from the bar 218 includes a lost motion connection that insures tight, bag-retaining relation between the fingers 248 and the bar 218 as the gripper assembly F moves away from the belts B.

The chain 208 continues to move in the direction of the arrow X in Fig. 10 and the bag I remains suspended from the gripping assembly F in the manner illustrated in Fig. 11. When the conveyor G is reached (Fig. 12), the bag J will be drawn across the top thereof until the gripping assembly F reaches the sprocket 204. When the gripping assembly F reaches the sprocket 204, it will be opened in passing therearound and the bag I will drop onto the conveyor G so as to lie flat thereupon, unless, of course, the bag is longer than the conveyor G is wide, in which case the bag will drape itself over the conveyor G in the manner illustrated in Fig. 12.

Simultaneously with the release of the bag I by the gripping assembly F, the cam 272 will actuate the arms 260 and 262 in the manner previously described to press the bag I downwardly against the conveyor G and prevent the bag from slipping off or altering its position on the conveyor because of an air cushion thereunder. In Fig. 12 it can be seen that at this time the succeeding bag J has issued from the bag making machine between the knife blades 62 and 66 and is about to be contacted by the bar D associated with the other gripping assembly F. The conveyor G will remain stationary while the bag I is carried to and dropped onto the bag I already in position upon the conveyor G, and this operation will be repeated a number of times depending upon the spacing between the notches 326 in the cam plate 324. Thus a stack of neatly piled bags will accumulate on the conveyor G until the stack contains the desired number of bags, whereupon the cam 336 will actuate the switch 332 and thereby eifect advancement of the conveyor G so that the next stack of bags will be formed either in position spaced laterally from the completed stack or in offset, overlapping relation thereupon, depending upon the selected adjustment of the cam plates 338 and 340. It will be understood, therefore, that the stacking machine of the invention operates automatically to receive bags successively from a bag making machine or other source, and to stack them neatly in spaced apart or relatively offset piles, each of which contains a predetermined number of the bags.

While a preferred embodiment of the invention has been disclosed herein, it is evident that various changes may be made therein without departing from the spirit of the invention as definedin the appended claims.

Having thus described my invention, what I claim to be new and desire to protect by Letters Patent is:

1. A bag stacking mechanism for use with a bag handling machine comprising a first conveying mechanism adapted to receive bags as they are successively discharged by said bag handling machine, a second conveying mechanism mounted with its forward end above said first conveying mechanism and its rearmost end spaced rearwardly from the rearmost end of said first conveying mechanism, a gripping assembly carried by said second conveying mechanism adapted to grip the trailing edge of a bag on said first conveying mechanism, and means driving said bag handling machine said first conveying mechanism and said second conveying mechanism in timed relation with each other, whereby said gripping assembly will grip the trailing edge of a bag and carry said bag in suspended relation beyond the rearmost end of said first conveying mechanism, a discharge conveyor extending transversely beneath the rearmost end of said second conveyor, and means for releasing said gripping assembly adjacent the rearmost end of said second conveying mechanism to release the bags successively carried thereby and permit the bags to be deposited on said discharge conveyor in superposed relation, and means for periodically driving said discharge lconveyor to separate the bags deposited thereon into groups each containing a predetermined number of bags.

2. A bag stacking mechanism comprising a first conveyor adapted to receive the bags successively from a source of supply, an endless flexible conveyor adjacent said first conveyor and extending rearwardly therefrom along the line of movement of said first conveyor, the lower reach of said endless flexible conveyor being substantially tangent to the line of movement of said bags on said first conveyor, a gripping mechanism carried by said endless flexible conveyor and extending transversely thereof, means for opening said gripping mechanism as said gripping mechanism approaches said first conveyor and for subsequently closing said gripping mechanism to grip the trailing edge of a bag on said first conveyor, and means for operating said first conveyor and said endless flexible conveyor in timed relation with each other, whereby said gripping mechanism will engage and grip the trailing edge of a bag to convey said bag suspended from said gripping mechanism beyond the rear end of said first conveyor.

3. A bag stacking mechanism comprising a first conveyor adapted to receive bags successively from a source of supply, an endless flexible conveyor adjacent said first conveyor and extending rearwardly therefrom along the line of movement of said first conveyor, the lower reach of said endless flexible conveyor being substantially tangent to the line of movement of said bags on said first conveyor, a gripping mechanism carried by said endless flexible conveyor and extending transversely thereof, means for opening said gripping mechanism as said gripping mechanism approaches said first conveyor and for subsequently closing said gripping mechanism to grip the trailing edge of a bag on said first conveyor, means for operating said first conveyor and said endless flexible conveyor in timed relation with each other, whereby said gripping mechanism will engage and grip the trailing edge of a bag to convey said bag suspended from said gripping mechanism beyond the rear end of said first conveyor, a discharge conveyor extending transversely beneath said endless flexible conveyor adjacent the rearmost end thereof, and means for opening said gripping member adjacent the rearmost end of said endless flexible conveyor to release the bag and to permit it to be deposited on said discharge conveyor.

4. A bag stacking mechanism comprising a first conveyor adapted to receive the bags successively from a source of supply, an endless flexible conveyor adjacent I said first conveyor and extending rearwardly therefrom along the line of movement of said first conveyor, the lower reach of said endless flexible conveyor being substantially tangent to the line of movement of said bags on said first conveyor, a gripping mechanism carried by said endless flexible conveyor and extending transversely thereof, means for opening said gripping mechanism as said gripping mechanism aproaches said first conveyor and for subsequently closing said gripping mechanism to grip the trailing edge of a bag on said first conveyor, means for operating said first conveyor and said endless flexible conveyor in timed relation with each other, whereby said gripping mechanism will engage and grip the trailing edge of a bag to convey said bag suspended from said gripping mechanism beyond the rear end of said first conveyor, a discharge conveyor extending transversely beneath said endless flexible conveyor adjacent the rearrnost end thereof, means for opening said gripping member adjacent the rearmost end of said endless flexible conveyor to release the bags successively carried thereby and permit said bags to be deposited on said discharge conveyor in superposed relation, and means for periodically driving said discharge conveyor to separate the bags deposited thereon into groups each containing a predetermined number of bags.

5. A bag stacking mechanism for stacking bags made of polyethylene film or the like comprising a first conveyor adapted to receive the bags successively from a source of supply, means adjacent said first conveyor to cause the discharge of any static charge from the surface of said bags, an endless flexible conveyor adjacent said first conveyor'and extending rearwardly therefrom along the line of movement of said first conveyor, the lower reach of said endless flexible conveyor being substantially tangent to the line of movement of said bags on said first conveyor, agripping mechanism carried by said endless flexible conveyor and extending transversely thereof, means for opening said gripping mechanism as said gripping mechanism approaches said first conveyor and for subsequently closing said gripping mechanism to grip the trailing edge of a bag on said first conveyor, and means for operating said first conveyor and said'endless flexible conveyor in timed relation with each other whereby said gripping mechanism will engage and grip the trailing edge of a bag, the portion of the lower reach of said endless flexible conveyor which extends beyond said first conveyor being disposed to have a predetermined clearance therebelow so that a bag suspended from said gripping mechanism will be free of static charge-forming contact with any surface.

6. A bag stacking mechanism for stacking bags made of polyethylene film or the like comprising a first conveyor adapted to receive the bags successively from a source of supply, means adjacent said first conveyor to cause the discharge of any static charge from the surface of said bags, an endless flexible conveyor adjacent said first conveyor and extending rearwardly therefrom along the. line of movement of said first conveyor, the lower reach of said endless flexible conveyor being substantially tangent to the line of movement of said bags on said first conveyor, a gripping mechanism carried by said endless flexible conveyor and extending transversely thereof, means for opening said gripping mechanism as said gripping mechanism approaches said first conveyor and for subsequently closing said gripping mechanism to grip the trailing edge of a bag on said first conveyor, and means for operating said first conveyor and said endless flexible conveyor in timed relation with each other whereby said gripping mechanism will engage and grip the trailing edge of a bag, the portion of the lower reach of said endless flexible conveyor which extends beyond said first conveyor being disposed to have a predetermined clearance therebelow so that a bag suspended from said gripping mechanism will be free of static charge-forming contact with any surface, a discharge conveyor extending transversely beneath said endless flexible conveyor adjacent the rearmost end thereof, and means for opening said gripping member. adjacent the rearmost end of said endless flexible conveyor to release the bag and permit it to be deposited on said discharge conveyor.

7. A bag stacking mechanism for stacking bags made of polyethylene film or the like comprising a first conveyor adapted to receive the bags successively from a source of supply, means adjacent said first conveyor to cause the discharge of any static charge from the surface of said bags, an endless flexible conveyor adjacent said first conveyor and extending rearwardly therefrom along the line of movement of said first conveyor, the lower reach of said endless flexible conveyor being substantially tangent to the line of movement of said bags on said first conveyor, a gripping mechanism carried by said endless flexible conveyor and extending transversely thereof, means for opening said gripping mechanism as said gripping mechanism approaches said first conveyor and for subsequently closing said gripping mechanism to grip the trailing edge of a bag on said first conveyor, and means for operating said first conveyor and said endless flexible conveyor in timed relation with each other whereby said gripping mechanism will engage and grip the trailing edge of a bag, the portion of the lower reach of said endless flexible conveyor which extends beyond said first conveyor being disposed to have a predetermined clearance therebelow so that a bag suspended from said gripping mechanism will be free of static charge-forming contact with any surface, a discharge conveyor extending transversely beneath said endless flexible conveyor adjacent the rearmost end thereof, means for opening said gripping member adjacent the rearmost end of said enless flexible conveyor to release the bags successively carried thereby and permit said bags to be deposited on said discharge conveyor in superposed relation, and means for periodically driving said discharge conveyor to separate the bags deposited thereon into groups each containing a predetermined number of bags.

8. In a bag stacking mechanism having an endless flexible conveyor trained around front and rear rotating members, a gripping assembly caried by said conveyor comprising a first transversely extending bar connected to said conveyor, a second bar mounted on said conveyor and extending parallel to and adjacent sm'd first bar, said second bar being mounted for rotation about its longitudinal axis, a plurality of gripping fingers carried by said second bar and adapted to be moved toward and away from abutting relation with the surface of said first bar by rotation of said second bar, and linkage interconnecting said second bar with said conveyor whereby said fingers are rotated away from said first bar as said gripping assembly progresses around each of said rotating members and are rotated into abutting relation with said first bar when said gripping assembly is between said rotating members.

9. In a bag stacking mechanism having an endless fiexible conveyor trained around front and rear rotating members, a gripping assembly carried by said conveyor comprising a first transversely extending bar connected to said conveyor, a second bar mounted on said conveyor and extending parallel to and adjacent the rear surface of said first bar, said second bar being mounted for rotation about its longitudinal axis, a plurality of gripping fingers carried by said second bar and adapted to be moved toward and away from abutting relation with the surface of said first bar by rotation of said second bar, and linkage intercoimecting said second bar with said conveyor whereby said fingers are rotated away from said first bar as said gripping assembly progresses around each of said rotating members and are rotated into abutting relation with said first bar when said gripping assembly is between said rotating members.

10. In a bag stacking mechanism having an endless flexible conveyor trained around front and rear rotating members, a gripping assembly carried by said conveyor comprising a first transversely extending bar mounted on said conveyor and connected to said conveyor, a second bar extending parallel to and adjacent the rear surface of said first bar, said second bar being mounted for rotation about its longitudinal axis, a plurality of gripping fingers carried by said second bar and adapted to be moved toward and away from abutting relation with the surface of said first bar by rotation of said second bar, a crank arm connected to said second bar, and a link connecting said crank arm with said conveyor at a point spaced rearwardly from said first bar, whereby said fingers are rotated away from said first bar as said gripping assembly progresses around each of said rotating members and are rotated into abutting relation with said CII.

12 first bar when said grippingassem'bly is between said rotating members. i

11. A stacking mechanism for sheet like material comprising a first conveyor adapted to receive sheets successively from a source of supply, a first rotatable mem' ber adjacent said first conveyor, a second rotatable member spaced from said first rotatable member, an endless conveyor trained around said rotatable members, the reach of said endless conveyor leaving said first rotatable member being substantially tangent to the line of movement of the sheets on said first conveyor, a gripping assembly carried by said endless conveyor adapted to grip the trailing edge of a sheet on said first conveyor, a bar mounted on said endless conveyor and extending transversely thereof in advance of said gripping mechanism to clamp said sheet against the support surface of said first conveyor until the trailing edge of said sheet is gripped by said gripping mechanism, and means driving said first conveyor and said endless conveyor in timed relation with each other, whereby said gripping assembly will grip the trailing edge of a sheet and carry said sheet in suspended relation beyond the rearmost end of said first conveyor.

12. In a bag stacking mechanism having an endless flexible conveyor trained around front and rear rotating members, a gripping assembly carried by said conveyor comprising a first bar connected to said conveyor, a second bar extending parallel to and adjacent said first bar, said second bar being mounted for rotation about its longitudinal axis, a plurality of gripping fingers carried by said second bar and adapted to be moved toward and away from abutting relation with the surface of said first bar by rotation of said second bar, torsion spring means connected to said second bar for biasing said second bar in a direction to bring said gripping fingers into abutting relation with said first bar, linkage interconnecting said second bar with said conveyor whereby said fingers are rotated away from said first bar as said gripping assembly progresses around each of said rotating members and are rotated into abutting relation with said first bar when said gripping assembly is between said rotating members, and a lost motion connection between said linkage and said conveyor to insure tight abutting relation between said gripping fingers and said first bar under the influence of said spring means when said gripping assembly is between said rotating members.

13. A bag stacking mechanism for use with a bag handling machine comprising a first conveying mechanism adapted to receive bags as they are successively discharged by said bag handling machine, a second conveying mechanism mounted with its forward end above said first conveying mechanism and its rearmost end spaced rearwardly from the rearmost end of said first conveying mechanism, a gripping assembly carried by said second conveying mechanism adapted to grip the trailing edge of a bag on said first conveying mechanism, means driving said bag handling machine said first conveying mechanism and said second conveying mechanism in timed relation with each other, whereby said gripping assembly will grip the trailing edge of a bag and cany said bag in suspended relation beyond the rearmost end of said first conveying mechanism, a discharge conveyor extending transversely beneath the rearmost end of said second conveyor, means for releasing said gripping assembly at a point above said discharge conveyor to release the bags successively carried thereby and permit the bags to be deposited on said discharge conveyor in superposed relation, a pair of rotatably mounted shafts extending transverse to the direction of movement of said second conveying mechanism, a bag depressing arm mounted on each of said shafts, means interconnecting said shafts for conjoint movement, spring means connected between one of said shafts and the frame of said second conveying mechanism, a cam follower connected to the other of said shafts, cam means adapted to operate said cam follower to rotate said shafts against the action of said spring means to depress said bag depressing arms against the uppermost bag on said discharge conveyor to force out any air from beneath said uppermost bag, and means for driving said cam means in timed relation with said second conveying mechanism.

14. In a bag stacking mechanism, a support, means for successively discharging bags in superposed relation on said support, a pair of rotatably mounted shafts extending transverse to the direction of movement of said ba'g discharging means, a bag depressing arm mounted on each of the said shafts, means interconnecting said shafts for conjoint movement, spring means connected between one of said shafts and the frame of said bag discharging means, a cam follower connected to the other of said shafts, cam means adapted to operate said cam follower to rotate said shafts against the action of said spring means to depress said bag depressing arms against the uppermost bag on said support to force out any air from beneath said uppermost bag, and means for driving said cam means in timed relation with said bag discharging means.

15. In a bag stacking mechanism, a support, means for successively discharging bags in superposed relation on said support, a pair of rotatably mounted shafts extending transverse to the direction of movement of said bag discharging means, a bag depressing arm mounted on each of said shafts, a sprocket on each of said shafts, a chain connecting said sprockets, whereby said shafts are interconnected for conjoint movement, spring means connected between one of said shafts and the frame of said bag discharging means, a cam follower connected to the other of said shafts, cam means adapted to operate said cam follower to rotate said shafts against the action of said spring means to depress said bag depressing arms against the uppermost bag on said support to force out any air from beneath said uppermost bag, and means for driving said cam means in timed relation with said bag discharging means.

16. In a bag stacking mechanism, a support, means for successively discharging bags in superposed relation on said support, a pair of rotatably mounted shafts extending transverse to the direction of movement of said bag discharging means, a bag depressing arm mounted on each of said shatfts, a sprocket on each of said shafts, a chain connecting said sprockets, whereby said shafts are interconnected for conjoint movement, a torsion spring surrounding one end of one of said shafts and connected between said shaft and the frame of said bag discharging means, a cam follower connected to the other of said shafts, cam means adapted to operate said cam follower to rotate said shafts against the action of said torsion spring to depress said bag depressing arms against the uppermost bag on said support to force out any air from beneath said uppermost bag, and means for driving said cam means in timed relation with said bag discharging means.

References Cited in the file of this patent UNITED STATES PATENTS 1,087,473 Vierengel Feb. 17, 1914 1,462,923 Stevens July 24, 1923 2,355,697 Belluche Oct. 7, 1937 2,753,798 Babst July 10, 1956 FOREIGN PATENTS 473,337 Great Britain Oct. 7, 1937 

